Introduction: Personalized medicine (PM) is an important topic in public health. However, there is no consensus among its definitions. A recent study showed that familiarity with the medical field influences the definition of PM. Indeed, the most familiar people define it more technically with biomedical and genetic aspects, while the others only cite patient-centered aspects. In line with this study, our research proposes to replicate the effect of familiarity in a larger sample and to examine the role of genetic knowledge on the definition of PM. Methods: 427 participants (205 in general population and 222 students, with different study domains) were recruited. They answered to an online questionnaire evaluating the definition of PM, attitudes towards pharmacogenomics and general beliefs towards medicines. Moreover, the general population participants answered to a genetic knowledge questionnaire. Results: Independently of their study domain (scientific or not), participants characterize PM with both technical and patient-centered aspects. In the general population, the knowledge in genetics is significantly predictive of the definition of PM. The more genetically literate people are, the more they will define PM with genetic-related concepts. Conclusions: The findings could lead to an improvement of patient care by taking into account knowledge in genetics. PM being a frequent tool in cancer care, it seems important for patients to understand what PM really implies in order to promote a better understanding and avoid oversized hopes.